A 6-month randomized, placebo-controlled, dose-ranging trial of topiramate for weight loss in obesity

Objective: To evaluate the efficacy and safety of topiramate (TPM) for weight loss in healthy obese subjects. Research Methods and Procedures: A randomized, double-blind, placebo-controlled, dose-ranging trial was conducted. Three hundred eighty-five subjects, 18 and 75 years of age, were randomized to receive either placebo or TPM at 64, 96, 192, or 384 mg daily. Dosing began at 16 mg once daily. In week 2, the dose was increased to 16 mg twice daily. Thereafter, the dose was raised every week by 32 mg/d (16 mg twice daily) until subjects reached their target dose. Twenty-four weeks after beginning treatment, all subjects were tapered off treatment by a dose reduction of 50% per week. All participants received the same lifestyle program. Results: Mean percent weight loss from baseline to week 24 was -2.6% in placebo-treated patients vs. -5.0%, -4.8%, -6.3%, and -6.3% in the 64, 96, 192, and 384 mg/d TPM groups, respectively. Greater percentages of TPM-treated patients lost at least 5% or 10% of body weight compared with placebo. The most frequent adverse events were related to the central or peripheral nervous system, including paresthesia, somnolence, and difficulty with memory, concentration, and attention. Most events were dose-related, occurred early in treatment, and usually resolved spontaneously; only 21% receiving TPM withdrew due to adverse events compared with 11% on placebo. Discussion: TPM produced significantly greater weight loss than placebo at all doses.